Evaluation of the reproducibility of a protocol for the pharmacokinetic study of breast tumors by dynamic magnetic resonance imaging

Abstract

Objective: To evaluate the reproducibility of a protocol for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the pharmacokinetic study of breast tumors.

Material and methods: We carried out this prospective study from October 2009 through December 2009. We studied 12 patients with stage ii-iii invasive breast cancer without prior treatment. Our center's research ethics committee approved the study. The 12 patients underwent on two consecutive days DCE-MRI with a high temporal resolution protocol (21 acquisitions/minute). The data obtained in an ROI traced around the largest diameter of the tumor (ROI 1) and in another ROI traced around the area of the lesion's highest K(trans) intensity (ROI 2) were analyzed separately. We used parametric and nonparametric statistical tests to study the reproducibility and concordance of the principal pharmacokinetic variables (K(trans), Kep, Ve and AUC90).

Results: The correlations were very high (r>.80; P<.01) for all the variables for ROI 1 and high (r=.70-.80; P<.01) for all the variables for ROI 2, with the exception of Ve both in ROI 1 (r=.44; P=.07) and in ROI 2 (r=.13; P=.235). There were no statistically significant differences between the two studies in the values obtained for K(trans), Kep and AUC90 (P>.05 for each), but there was a statistically significant difference between the two studies in the values obtained for Ve in ROI 2 (P=.008).

Conclusions: The high temporal resolution protocol for DCE-MRI used at out center is very reproducible for the principal pharmacokinetic constants of breast.

Keywords: Breast cancer; Cáncer de mama; Farmacocinética; Imagen por resonancia magnética; Magnetic resonance imaging; Pharmacokinetics.